ltc2950-1 Linear Technology Corporation, ltc2950-1 Datasheet - Page 6

• Manufacturer Part Number: ltc2950-1
• Description: Push Button On/off Controller
• Manufacturer: Linear Technology Corporation

PIN FUNCTIONS
LTC2950-1/LTC2950-2
6
V
PB (Pin 2/Pin 3): Push Button Input. Connecting PB to
ground through a momentary switch provides on/off
control via the EN/EN pin. An internal 100k pull-up resis-
tor connects to an internal 1.9V bias voltage. The rugged
PB input can be pulled up to 26.4V externally without
consuming extra current.
ONT (Pin 3/Pin 2): Additional Adjustable Turn On Time
Input. Placing an external capacitor to ground determines
the additional time (beyond the internal default 32ms)
the PB pin must be held low before the enable output
is asserted. Floating this pin results in a default turn on
debounce time of 32ms.
GND (Pin 4/Pin 1): Device Ground.
INT (Pin 5/Pin 8): Open Drain Interrupt Output. After a push
button turn-off event is detected, the LTC2950 interrupts the
system (μP) by bringing the INT pin low. Once the system
fi nishes its power down and housekeeping tasks, it sets
KILL low, which in turn releases the enable output. If at the
end of the power down timer (1024ms) KILL is still high, the
enable output is released immediately. INT may optionally
be tied to KILL to release the enable output immediately
after the turn-off event has been detected (INT = low).
EN (LTC2950-1, Pin 6/Pin 7): Open Drain Enable Output.
This pin is intended to enable system power. EN is as-
serted high after a valid PB turn on event. EN is released
low if: a) KILL is not driven high (by μP) within 512ms of
the initial valid PB power turn-on event, b) KILL is driven
low during normal operation, c) a second valid PB event
(power turn-off) is detected. The operating range for this
pin is 0V to 10V.
IN
(Pin 1/Pin 4): Power Supply Input: 2.7V to 26.4V.
(TSOT-23/DFN)
EN (LTC2950-2, Pin 6/Pin 7): Open Drain Enable Output.
This pin is intended to enable system power. EN is as-
serted low after a valid PB turn-on event. EN releases
high if: a) KILL is not driven high (by μP) within 512ms of
the initial valid PB power turn-on event, b) KILL is driven
low during normal operation, c) a second valid PB event
(power turn-off) is detected. The operating range of this
pin is 0V to 10V.
OFFT (Pin 7/Pin 6): Additional Adjustable Turn Off Time
Input. A capacitor to ground determines the additional
time (beyond the internal default 32ms) that the PB pin
must be held low before initiating a power down sequence
(INT falling). Floating this pin results in a default turn off
time of 32ms.
KILL (Pin 8/Pin 5): KILL Input. Forcing KILL low releases
the enable output. During system turn on, this pin is
blanked by a 512ms internal timer to allow the system to
pull KILL high. This pin has an accurate 0.6V threshold
and can be used as a voltage monitor input.
Exposed Pad (Pin 9): Exposed Pad may be left open or
connected to device ground.
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